The present invention relates to over-current protection devices, and more specifically to over-current protection devices for preventing over-current faults caused by short-circuit faults.
Over-current protection devices are commonly employed in switch mode power supplies (SMPS) to monitor and prevent excessive currents from forming within the SMPS. Typically, if the monitored current exceeds a defined threshold, the over-current protection device causes the switch providing power to the load to open, preventing additional power from being provided to the load and thereby limiting the current through the SMPS. However, despite the use of traditional over-current protection devices, conditions may occur that result in the generation of large currents in the SMPS. In particular, short-circuit faults experienced by a SMPS may result in a condition known as current runaway, or current ratcheting, in which load currents within a SMPS become progressively larger despite typical over-current protection methods.